This seems like a big overreaction at this point. Yeah Microsoft has made some big acquisitions but are we pretending that Sony doesn't also have a ton of studios making good games under their belt? - Guerilla, Insomnia, Naughty Dog, Santa Monica, Sucker Punch, Housemarque, etc...
Plus Sony has like $10B left set aside for acquisitions which means we still have no clue what the landscape will even be at this point.
Yes, it does seem very premature. Microsoft is committed to keeping games available on the PlayStation through existing agreements and beyond. So to me that says if it becomes an issue, it will be on the next gen platforms. The PS5 should not feel an impact.
I suspect most games will continue to be on multiple platforms. Call of Duty is really the only game that comes to mind that is at risk of becoming of Xbox exclusive at some point.